Atmosphere (대기)

Korean Meteorological Society (한국기상학회)
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Characteristics of the Gross Moist Stability in the Tropics and Its Future Change

열대 지역 Gross Moist Stability 특징 분석 및 미래 변화

  • Kim, Hye-Won (Division of Earth Environmental System, Pusan National University) ;
  • Seo, Kyong-Hwan (Department of Atmospheric Sciences, Pusan National University)
  • 김혜원 (부산대학교 지구환경시스템학부) ;
  • 서경환 (부산대학교 대기환경과학과)
  • Received : 2013.12.09
  • Accepted : 2014.01.22
  • Published : 2014.06.30
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Abstract

This study investigates the characteristics of the Gross Moist Stability (GMS) over the tropics. The GMS summarizes the relationship between large-scale entropy forcing due to radiation and surface fluxes and the response of smaller-scale convection. The GMS is able to explain both to where moist entropy is advected by the atmospheric circulation and how deep the moisture flux convergence is in the tropical region. In the deep convective region, positive GMS appears over the warm pool region due to the strong column-integrated moisture convergence and the ensuing export of moist entropy to the environment. The vertical advection of moist entropy dominates over the horizontal advection in this region. Meanwhile, over the eastern tropical ITCZ region, which is characterized by shallow convective area, import of moist entropy by horizontal winds is dominant compared to the vertical moist entropy advection. Future changes in the GMS are also examined using the 22 CMIP5 model simulations. A decrease in the GMS appears widely across the tropics, but its increase occurs over the western-central equatorial Pacific. It is evident that the increased GMS region corresponds to an increased region of precipitation, implying that strengthened convection in the future due to increased entropy forcing exports the enhanced moist energy to stabilize the environment.

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References

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